[Equipment] Proprietary Dreamstation Battery Cables?

[carastas]

Hi, I figured it out. I chained 3 10k potentiometers and turned them until the warning disappeared. I expected to have to reset the unit every time but it works real time. (for future reference). -12v on the outside battel, +12v on the inside barrel, around 20k on the small inner wire.

[SuperSleeper]

Here's a 30k Potentiometer for about $12 US:

https://www.amazon.com/Taiss-RV24YN20S-P...074KHKKGQ/

That would work, I would assume..

If possible, could you post a basic schematic (or pics) for how you wired it up?

[carastas]

Here is a schematic. I swear I spent half my life being paid for graphic design work

[alanbc]

Thanks for the image!

For the sake of accuracy, I should point out that the outer barrel is not "-12v", it is in fact "0v".

What you have drawn is something that runs on 24 volts dc.  The Dreamstation runs on 12 volts dc.

[Pastrywagon]

I just bought this cable on Amazon (not sure if I can post the link on here but search for this):

DC Output Cable Adapter DreamStation 2 for Medistrom Pilot-12 Lite  ($16.97)

It looks like the exact same plug as the original wall adapter and I am betting it already has the resistor installed in the tip since it claims to be compatible.  The other end looks like it will fit my battery outlet perfectly.  I will keep you posted.

I also ordered this:

UpBright Car 12V DC Adapter Compatible with Philips Respironics DreamStation 2  ($16.99)

I will respond here when I get it and let ya'll know if it worked.

Neither cable has the giant ferrules, which is a plus for running off a battery in my opinion.

Otherwise, HP and some Dell computers use this barrel plug, however I haven't seen any with a 90 degree bend.  You could use the old one off your System One or Dreamstation but it may not fit inside the hole for this new plug.  Also, I'm not sure they have a wire for the center pin in the harness.

So I put a meter on my factory power supply center pin and measured 24.2k ohms to the positive (center barrel) and 29k ohms to the negative (outer barrel).  Why would it be connected to both with a resistor?  I think I have seen this before on Iphone chargers.  One of these days I will put one together and see if it works.  For now, my fingers are crossed that the Amazon cables will work.

[Pastrywagon]

Both cables worked great. The Medistrom cable has a better connecter that matches the factory cable almost perfectly. It's easier to remove and can go under the machine like the original. The UpBright cable doesn't have a full 90 degree bend on it which is not great for putting into the machine. I took a heat gun and warmed the plastic up and bent it to the full 90 degrees and held it while the cable cooled. Now it works fine.

I put a meter on the center pin to measure resistance to both the positive and negative wires:
The Medistrom cable has 1 million ohms between the center pin and the negative side (outside of the barrel). I can't find any resistance between the center pin and positive.
The UpBright cable has the standard 20,000 ohm resistor between the center pin and positive side (inside of the barrel connector). The meter shows no connection to the negative side.

My complaints about the new machine so far:
I am annoyed that the power connector is on the bottom of the machine. It makes it nearly impossible to use any connector that is not perfectly matched to the opening. I don't like that the humidifier cannot be removed like in the System One. That was a nice option for camping and backpacking. Also, the fact that you have to turn the machine on before you can adjust the humidifier settings is idiotic. If I have a battery source with limited amp capacity I may not be able to turn off the humidifier before the power source shuts off due to pulling too much power. Terrible design choice. All of my camping batteries use either 6 or 8 18650 lithium cells and can only put out about 3 amps. They work fine with the humidifier off. So now I have to remember to shut the humidifier off before leaving home.